SummaryThe overall goal of 14Constraint is to enhance the availability and use of radiocarbon data as constraints for process-based understanding of the age distribution of carbon in and respired by soils and ecosystems. Carbon enters ecosystems by a single process, photosynthesis. It returns by a range of processes that depend on plant allocation and turnover, the efficiency and rate of litter decomposition and the mechanisms stabilizing C in soils. Thus the age distribution of respired CO2 and the age of C residing in plants, litter and soils are diagnostic properties of ecosystems that provide key constraints for testing carbon cycle models. Radiocarbon, especially the transit of ‘bomb’ 14C created in the 1960s, is a powerful tool for tracing C exchange on decadal to centennial timescales. 14Constraint will assemble a global database of existing radiocarbon data (WP1) and demonstrate how they can constrain and test ecosystem carbon cycle models. WP2 will fill data gaps and add new data from sites in key biomes that have ancillary data sufficient to construct belowground C and 14C budgets. These detailed investigations will focus on the role of time lags caused in necromass and fine roots, as well as the dynamics of deep soil C. Spatial extrapolation beyond the WP2 sites will require sampling along global gradients designed to explore the relative roles of mineralogy, vegetation and climate on the age of C in and respired from soil (WP3). Products of this 14Constraint will include the first publicly available global synthesis of terrestrial 14C data, and will add over 5000 new measurements. This project is urgently needed before atmospheric 14C levels decline to below 1950 levels as expected in the next decade.

The overall goal of 14Constraint is to enhance the availability and use of radiocarbon data as constraints for process-based understanding of the age distribution of carbon in and respired by soils and ecosystems. Carbon enters ecosystems by a single process, photosynthesis. It returns by a range of processes that depend on plant allocation and turnover, the efficiency and rate of litter decomposition and the mechanisms stabilizing C in soils. Thus the age distribution of respired CO2 and the age of C residing in plants, litter and soils are diagnostic properties of ecosystems that provide key constraints for testing carbon cycle models. Radiocarbon, especially the transit of ‘bomb’ 14C created in the 1960s, is a powerful tool for tracing C exchange on decadal to centennial timescales. 14Constraint will assemble a global database of existing radiocarbon data (WP1) and demonstrate how they can constrain and test ecosystem carbon cycle models. WP2 will fill data gaps and add new data from sites in key biomes that have ancillary data sufficient to construct belowground C and 14C budgets. These detailed investigations will focus on the role of time lags caused in necromass and fine roots, as well as the dynamics of deep soil C. Spatial extrapolation beyond the WP2 sites will require sampling along global gradients designed to explore the relative roles of mineralogy, vegetation and climate on the age of C in and respired from soil (WP3). Products of this 14Constraint will include the first publicly available global synthesis of terrestrial 14C data, and will add over 5000 new measurements. This project is urgently needed before atmospheric 14C levels decline to below 1950 levels as expected in the next decade.

Max ERC Funding

2 283 747 €

Duration

Start date: 2016-12-01, End date: 2021-11-30

Project acronymACCRETE

ProjectAccretion and Early Differentiation of the Earth and Terrestrial Planets

Researcher (PI)David Crowhurst Rubie

Host Institution (HI)UNIVERSITAET BAYREUTH

Call DetailsAdvanced Grant (AdG), PE10, ERC-2011-ADG_20110209

SummaryFormation of the Earth and the other terrestrial planets of our Solar System (Mercury, Venus and Mars) commenced 4.568 billion years ago and occurred on a time scale of about 100 million years. These planets grew by the process of accretion, which involved numerous collisions with smaller (Moon- to Mars-size) bodies. Impacts with such bodies released sufficient energy to cause large-scale melting and the formation of deep “magma oceans”. Such magma oceans enabled liquid metal to separate from liquid silicate, sink and accumulate to form the metallic cores of the planets. Thus core formation in terrestrial planets was a multistage process, intimately related to the major impacts during accretion, that determined the chemistry of planetary mantles. However, until now, accretion, as modelled by astrophysicists, and core formation, as modelled by geochemists, have been treated as completely independent processes. The fundamental and crucial aim of this ambitious interdisciplinary proposal is to integrate astrophysical models of planetary accretion with geochemical models of planetary differentiation together with cosmochemical constraints obtained from meteorites. The research will involve integrating new models of planetary accretion with core formation models based on the partitioning of a large number of elements between liquid metal and liquid silicate that we will determine experimentally at pressures up to about 100 gigapascals (equivalent to 2400 km deep in the Earth). By comparing our results with the known physical and chemical characteristics of the terrestrial planets, we will obtain a comprehensive understanding of how these planets formed, grew and evolved, both physically and chemically, with time. The integration of chemistry and planetary differentiation with accretion models is a new ground-breaking concept that will lead, through synergies and feedback, to major new advances in the Earth and planetary sciences.

Formation of the Earth and the other terrestrial planets of our Solar System (Mercury, Venus and Mars) commenced 4.568 billion years ago and occurred on a time scale of about 100 million years. These planets grew by the process of accretion, which involved numerous collisions with smaller (Moon- to Mars-size) bodies. Impacts with such bodies released sufficient energy to cause large-scale melting and the formation of deep “magma oceans”. Such magma oceans enabled liquid metal to separate from liquid silicate, sink and accumulate to form the metallic cores of the planets. Thus core formation in terrestrial planets was a multistage process, intimately related to the major impacts during accretion, that determined the chemistry of planetary mantles. However, until now, accretion, as modelled by astrophysicists, and core formation, as modelled by geochemists, have been treated as completely independent processes. The fundamental and crucial aim of this ambitious interdisciplinary proposal is to integrate astrophysical models of planetary accretion with geochemical models of planetary differentiation together with cosmochemical constraints obtained from meteorites. The research will involve integrating new models of planetary accretion with core formation models based on the partitioning of a large number of elements between liquid metal and liquid silicate that we will determine experimentally at pressures up to about 100 gigapascals (equivalent to 2400 km deep in the Earth). By comparing our results with the known physical and chemical characteristics of the terrestrial planets, we will obtain a comprehensive understanding of how these planets formed, grew and evolved, both physically and chemically, with time. The integration of chemistry and planetary differentiation with accretion models is a new ground-breaking concept that will lead, through synergies and feedback, to major new advances in the Earth and planetary sciences.

Max ERC Funding

1 826 200 €

Duration

Start date: 2012-05-01, End date: 2018-04-30

Project acronymC2Phase

ProjectClosure of the Cloud Phase

Researcher (PI)Corinna HOOSE

Host Institution (HI)KARLSRUHER INSTITUT FUER TECHNOLOGIE

Call DetailsStarting Grant (StG), PE10, ERC-2016-STG

SummaryWhether and where clouds consist of liquid water, ice or both (i.e. their thermodynamic phase distribution), has major impacts on the clouds’ dynamical development, their radiative properties, their efficiency to form precipitation, and their impacts on the atmospheric environment. Cloud ice formation in the temperature range between 0 and -37°C is initiated by aerosol particles acting as heterogeneous ice nuclei and propagates through the cloud via a multitude of microphysical processes. Enormous progress has been made in recent years concerning the understanding and model parameterization of primary ice formation. In addition, high-resolution atmospheric models with complex cloud microphysics schemes can now be employed for realistic case studies of clouds. Finally, new retrieval schemes for the cloud (top) phase have recently been developed for various satellites, including passive polar orbiting and geostationary sensors, which provide a good spatial and temporal coverage and a long data record.
We propose here to merge the bottom-up, forward modeling approach for the cloud phase distribution with the top-down view of satellites. C2Phase will conduct systematic closure studies for variables related to the cloud phase distribution such as the cloud ice area fraction, its distribution as function of temperature and its temporal evolution, with a focus on Europe. For this, we will (1) use clustering techniques to separate different cloud regimes in model and satellite data, (2) explore the parameters and processes which the simulated phase distribution is most sensitive to, (3) investigate whether closure is reached between state-of-the art cloud resolving models and satellite observations, and how this closure can be improved by consistent and physically justified changes in microphysical parameterizations, and (4) use our results to improve the representation of mixed-phase clouds in weather and climate models and to quantify the impacts of these improvements.

Whether and where clouds consist of liquid water, ice or both (i.e. their thermodynamic phase distribution), has major impacts on the clouds’ dynamical development, their radiative properties, their efficiency to form precipitation, and their impacts on the atmospheric environment. Cloud ice formation in the temperature range between 0 and -37°C is initiated by aerosol particles acting as heterogeneous ice nuclei and propagates through the cloud via a multitude of microphysical processes. Enormous progress has been made in recent years concerning the understanding and model parameterization of primary ice formation. In addition, high-resolution atmospheric models with complex cloud microphysics schemes can now be employed for realistic case studies of clouds. Finally, new retrieval schemes for the cloud (top) phase have recently been developed for various satellites, including passive polar orbiting and geostationary sensors, which provide a good spatial and temporal coverage and a long data record.
We propose here to merge the bottom-up, forward modeling approach for the cloud phase distribution with the top-down view of satellites. C2Phase will conduct systematic closure studies for variables related to the cloud phase distribution such as the cloud ice area fraction, its distribution as function of temperature and its temporal evolution, with a focus on Europe. For this, we will (1) use clustering techniques to separate different cloud regimes in model and satellite data, (2) explore the parameters and processes which the simulated phase distribution is most sensitive to, (3) investigate whether closure is reached between state-of-the art cloud resolving models and satellite observations, and how this closure can be improved by consistent and physically justified changes in microphysical parameterizations, and (4) use our results to improve the representation of mixed-phase clouds in weather and climate models and to quantify the impacts of these improvements.

Max ERC Funding

1 499 549 €

Duration

Start date: 2017-04-01, End date: 2022-03-31

Project acronymCCMP

ProjectPhysics Of Magma Propagation and Emplacement: a multi-methodological Investigation

SummaryDikes and sills are large sheet-like intrusions transporting and storing magma in the Earth’s crust.
When propagating, they generate seismicity and deformation and may lead to volcanic eruption. The physics of magma-filled structures is similar to that of any fluid-filled reservoir, such as oil fields and CO2 reservoirs created by sequestration. This project aims to address old and new unresolved challenging questions related to dike propagation, sill emplacement and in general to the dynamics of fluid and gas-filled reservoirs. I propose to focus on crustal deformation, induced seismicity and external stress fields to study the signals dikes
and sills produce, how they grow and why they reactivate after years of non-detected activity. I will combine experimental, numerical and analytical techniques, in close cooperation with volcano observatories providing us with the data necessary to validate our models. In the lab, I will simulate magma propagation injecting fluid into solidified gelatin. I will also contribute to a project, currently under evaluation, on the monitoring of a CO2
sequestration site. At the same time, I will address theoretical aspects, extending static models to dynamic cases and eventually developing a comprehensive picture of the multi faceted interaction between external stress field,
magma and rock properties, crustal deformation and seismicity. I also plan, besides presenting my team’s work in the major national and international geophysical conferences, to produce, with technical support from the media services of DKRZ (Deutsches Klimarechenzentrum), an audiovisual teaching DVD illustrating scientific advances and unresolved issues in magma dynamics, in the prediction of eruptive activity and in the physics of reservoirs.

Dikes and sills are large sheet-like intrusions transporting and storing magma in the Earth’s crust.
When propagating, they generate seismicity and deformation and may lead to volcanic eruption. The physics of magma-filled structures is similar to that of any fluid-filled reservoir, such as oil fields and CO2 reservoirs created by sequestration. This project aims to address old and new unresolved challenging questions related to dike propagation, sill emplacement and in general to the dynamics of fluid and gas-filled reservoirs. I propose to focus on crustal deformation, induced seismicity and external stress fields to study the signals dikes
and sills produce, how they grow and why they reactivate after years of non-detected activity. I will combine experimental, numerical and analytical techniques, in close cooperation with volcano observatories providing us with the data necessary to validate our models. In the lab, I will simulate magma propagation injecting fluid into solidified gelatin. I will also contribute to a project, currently under evaluation, on the monitoring of a CO2
sequestration site. At the same time, I will address theoretical aspects, extending static models to dynamic cases and eventually developing a comprehensive picture of the multi faceted interaction between external stress field,
magma and rock properties, crustal deformation and seismicity. I also plan, besides presenting my team’s work in the major national and international geophysical conferences, to produce, with technical support from the media services of DKRZ (Deutsches Klimarechenzentrum), an audiovisual teaching DVD illustrating scientific advances and unresolved issues in magma dynamics, in the prediction of eruptive activity and in the physics of reservoirs.

SummaryHow do erosion rates in glacial landscapes vary with climate change and how do such changes affect the dynamics of mountain glaciers? Providing quantitative constraints towards this question is the main objective of COLD. These constraints are so important because mountain glaciers are sensitive to climate change and their deposits provide a unique history of Earths terrestrial climate that allows reconstructing leads and lags in the climate system.
The climate sensitivity of mountain glaciers is influenced by debris on their surface that impedes ice melting. Theoretical models of frost-related bedrock fracturing predict that rates of debris production are temperature-sensitive and that its supply to mountain glaciers increases during warming periods. Thus a previously unrecognized negative feedback emerges that lowers ice melt rates and potentially buffers part of the ice retreat due to warming. However, the temperature-sensitivity of debris production in glacial landscapes is poorly understood. Specifically, we lack robust erosion rate estimates for these landscapes, which are key for testing models of frost-related bedrock fracturing.
Here, I propose an innovative combination of new tools that capitalize on recent developments in cosmogenic nuclide geochemistry, landscape evolution modelling, and planetary-scale remote sensing analysis. I will use these tools to quantify headwall erosion rates in mountainous glacial landscapes and to gauge the sensitivity of mountain glaciers to variations in debris supply. Expected results will provide a basis for assessing the impacts of global warming, for improved predictions of valley glacier evolution, and for palaeoclimate interpretations of glacial landforms. COLD will focus on glacial landscapes, but the inverse modelling approach I will develop is applicable to any landscape on Earth and has the potential to fundamentally transform how we use cosmogenic nuclides to constrain Earth surface dynamics.

How do erosion rates in glacial landscapes vary with climate change and how do such changes affect the dynamics of mountain glaciers? Providing quantitative constraints towards this question is the main objective of COLD. These constraints are so important because mountain glaciers are sensitive to climate change and their deposits provide a unique history of Earths terrestrial climate that allows reconstructing leads and lags in the climate system.
The climate sensitivity of mountain glaciers is influenced by debris on their surface that impedes ice melting. Theoretical models of frost-related bedrock fracturing predict that rates of debris production are temperature-sensitive and that its supply to mountain glaciers increases during warming periods. Thus a previously unrecognized negative feedback emerges that lowers ice melt rates and potentially buffers part of the ice retreat due to warming. However, the temperature-sensitivity of debris production in glacial landscapes is poorly understood. Specifically, we lack robust erosion rate estimates for these landscapes, which are key for testing models of frost-related bedrock fracturing.
Here, I propose an innovative combination of new tools that capitalize on recent developments in cosmogenic nuclide geochemistry, landscape evolution modelling, and planetary-scale remote sensing analysis. I will use these tools to quantify headwall erosion rates in mountainous glacial landscapes and to gauge the sensitivity of mountain glaciers to variations in debris supply. Expected results will provide a basis for assessing the impacts of global warming, for improved predictions of valley glacier evolution, and for palaeoclimate interpretations of glacial landforms. COLD will focus on glacial landscapes, but the inverse modelling approach I will develop is applicable to any landscape on Earth and has the potential to fundamentally transform how we use cosmogenic nuclides to constrain Earth surface dynamics.

Max ERC Funding

1 499 308 €

Duration

Start date: 2018-01-01, End date: 2022-12-31

Project acronymDARCLIFE

ProjectDeep subsurface Archaea: carbon cycle, life strategies, and role in sedimentary ecosystems

Researcher (PI)Kai-Uwe Hinrichs

Host Institution (HI)UNIVERSITAET BREMEN

Call DetailsAdvanced Grant (AdG), PE10, ERC-2009-AdG

SummaryArchaea are increasingly recognized as globally abundant organisms that mediate important processes controlling greenhouse gases and nutrients. Our latest work, published in PNAS and Nature, suggests that Archaea dominate the biomass in the subseafloor. Their unique ability to cope with extreme energy starvation appears to be a selecting factor. Marine sediments are of crucial importance to the redox balance and climate of our planet but the regulating role of the deep biosphere remains one of the great puzzles in biogeochemistry. The unique and diverse sedimentary Archaea with no cultured representatives, so-called benthic archaea, are key to understanding this system. Their presumed ability to degrade complex recalcitrant organic residues highlights their relevance for the carbon cycle and as potential targets for biotechnology. I propose to study the role of benthic archaea in the carbon cycle and in the deep biosphere and to explore their life strategies. This task requires an interdisciplinary frontier research approach at the scale of an ERC grant, involving biogeochemistry, earth sciences, and microbiology. Central to my research strategy is the information contained in structural and isotopic properties of membrane lipids from benthic archaea, an area of research spearheaded by my lab. In-depth geochemical examination of their habitat will elucidate processes they mediate. Metagenomic analysis will provide a phylogenetic framework and further insights on metabolism. At the Archaeenzentrum in Regensburg, we will grow model Archaea under a set of environmental conditions and examine the impact on cellular lipid distributions in order to develop the full potential of lipids as proxies for studying nearly inaccessible microbial life. Attempts to enrich benthic archaea from sediments will complement this approach. This frontier research will constrain the role of benthic archaea in the Earth system and examine the fundamental properties of life at minimum energy.

Archaea are increasingly recognized as globally abundant organisms that mediate important processes controlling greenhouse gases and nutrients. Our latest work, published in PNAS and Nature, suggests that Archaea dominate the biomass in the subseafloor. Their unique ability to cope with extreme energy starvation appears to be a selecting factor. Marine sediments are of crucial importance to the redox balance and climate of our planet but the regulating role of the deep biosphere remains one of the great puzzles in biogeochemistry. The unique and diverse sedimentary Archaea with no cultured representatives, so-called benthic archaea, are key to understanding this system. Their presumed ability to degrade complex recalcitrant organic residues highlights their relevance for the carbon cycle and as potential targets for biotechnology. I propose to study the role of benthic archaea in the carbon cycle and in the deep biosphere and to explore their life strategies. This task requires an interdisciplinary frontier research approach at the scale of an ERC grant, involving biogeochemistry, earth sciences, and microbiology. Central to my research strategy is the information contained in structural and isotopic properties of membrane lipids from benthic archaea, an area of research spearheaded by my lab. In-depth geochemical examination of their habitat will elucidate processes they mediate. Metagenomic analysis will provide a phylogenetic framework and further insights on metabolism. At the Archaeenzentrum in Regensburg, we will grow model Archaea under a set of environmental conditions and examine the impact on cellular lipid distributions in order to develop the full potential of lipids as proxies for studying nearly inaccessible microbial life. Attempts to enrich benthic archaea from sediments will complement this approach. This frontier research will constrain the role of benthic archaea in the Earth system and examine the fundamental properties of life at minimum energy.

Max ERC Funding

2 908 590 €

Duration

Start date: 2010-04-01, End date: 2015-03-31

Project acronymDarkMix

ProjectIlluminating the dark side of surface meteorology: creating a novel framework to explain atmospheric transport and turbulent mixing in the weak-wind boundary layer

Researcher (PI)Christoph Karl THOMAS

Host Institution (HI)UNIVERSITAET BAYREUTH

Call DetailsConsolidator Grant (CoG), PE10, ERC-2016-COG

SummarySurface meteorology impacts the abundance and quality of life on Earth through the transfer and mixing of light, heat, water, CO2, and other substances controlling the resources for humans, plants, and animals. However, current theories and models fail when airflows and turbulence are weak during calm nights leaving weather and climate forecasts uncertain. This ‘dark side’ occupies substantial fractions of time and our landscape, its physics are largely unknown, and has eluded proper experimental investigation.
DarkMix creates technological and theoretical innovations to observe and explain transport and mixing in the weak-wind boundary layer. Its ambitious goal is a radically new framework incorporating unexplored mechanisms such as submeso-scale motions, flow instationarities, and directional shear to effect a quantum leap in understanding the air-plant-soil exchange. DarkMix will build the ground-breaking first-ever fiber-optic distributed temperature sensing harp to fully resolve the 3-dimensional flow and air temperature fields and enable unprecedented computation of eddy covariance fluxes at scales of seconds over 4 orders of magnitude (deci- to hundreds of meters). Both key innovations bear significant risks of technical and fundamental nature, which are mitigated by pursuing alternatives. Measurements will inform cutting-edge large eddy simulations to test hypotheses. The interdisciplinary dimension takes DarkMix to a unique set of weak-wind sites including a valley-bottom grassland, a forest in complex terrain, and a city to investigate topographic effects, the forest carbon cycle, and the urban heat island.
DarkMix will open a new window for surface meteorology and its links to air quality, biogeochemistry, and climate change by giving physically meaningful and societally relevant answers to profound questions such as the exchange of greenhouse gases, hazards from ground fog, urban pollution, and agricultural losses through extreme cold air.

Surface meteorology impacts the abundance and quality of life on Earth through the transfer and mixing of light, heat, water, CO2, and other substances controlling the resources for humans, plants, and animals. However, current theories and models fail when airflows and turbulence are weak during calm nights leaving weather and climate forecasts uncertain. This ‘dark side’ occupies substantial fractions of time and our landscape, its physics are largely unknown, and has eluded proper experimental investigation.
DarkMix creates technological and theoretical innovations to observe and explain transport and mixing in the weak-wind boundary layer. Its ambitious goal is a radically new framework incorporating unexplored mechanisms such as submeso-scale motions, flow instationarities, and directional shear to effect a quantum leap in understanding the air-plant-soil exchange. DarkMix will build the ground-breaking first-ever fiber-optic distributed temperature sensing harp to fully resolve the 3-dimensional flow and air temperature fields and enable unprecedented computation of eddy covariance fluxes at scales of seconds over 4 orders of magnitude (deci- to hundreds of meters). Both key innovations bear significant risks of technical and fundamental nature, which are mitigated by pursuing alternatives. Measurements will inform cutting-edge large eddy simulations to test hypotheses. The interdisciplinary dimension takes DarkMix to a unique set of weak-wind sites including a valley-bottom grassland, a forest in complex terrain, and a city to investigate topographic effects, the forest carbon cycle, and the urban heat island.
DarkMix will open a new window for surface meteorology and its links to air quality, biogeochemistry, and climate change by giving physically meaningful and societally relevant answers to profound questions such as the exchange of greenhouse gases, hazards from ground fog, urban pollution, and agricultural losses through extreme cold air.

Max ERC Funding

1 898 104 €

Duration

Start date: 2017-05-01, End date: 2022-04-30

Project acronymDEEP

ProjectDeep Earth Elastic Properties and a Universal Pressure Scale

Researcher (PI)Daniel Frost

Host Institution (HI)UNIVERSITAET BAYREUTH

Call DetailsAdvanced Grant (AdG), PE10, ERC-2008-AdG

SummaryKnowledge of the physical and chemical state of the Earth s inner silicate mantle is central to our understanding of plate tectonics, mantle convection, magma generation and the composition of the Earth as a whole. The key to this knowledge is the ability to interpret studies of seismic wave velocities through the deep Earth using laboratory measurements of mineral sound velocities at high pressures and temperatures. Scientists have for many years measured these properties as a function of pressure but due to the experimental difficulties the majority of studies have been performed only at room temperature. Large extrapolations of these data to mantle temperatures are required to link seismic velocity observations with physical and chemical properties of mantle rocks, resulting in large uncertainties that obscure firm conclusions. An additional uncertainty arises because there is currently no primary scale for accurately measuring pressure at high temperatures. In this study mineral sound velocities and densities will be measured in the diamond anvil cell at simultaneous high pressures and high temperatures to at least 50 GPa and 1300K. This will be possible by a pioneering combination of Brillouin scattering spectroscopy, to measure sound velocities, and single crystal X-ray diffraction determinations of density. By making both types of measurements on the same sample while it is maintained at a constant pressure and temperature, the pressure can be independently measured. These absolute pressure determinations will be used to derive a new universal pressure scale for use at high temperatures. Sound velocities of the major mantle minerals will be determined at high temperatures and absolute pressures thereby drastically decreasing the uncertainties in velocity calculations for rock assemblages at deep mantle conditions. The resulting data will be employed to finally interpret a host of seismic observations made at both global and local scales.

Knowledge of the physical and chemical state of the Earth s inner silicate mantle is central to our understanding of plate tectonics, mantle convection, magma generation and the composition of the Earth as a whole. The key to this knowledge is the ability to interpret studies of seismic wave velocities through the deep Earth using laboratory measurements of mineral sound velocities at high pressures and temperatures. Scientists have for many years measured these properties as a function of pressure but due to the experimental difficulties the majority of studies have been performed only at room temperature. Large extrapolations of these data to mantle temperatures are required to link seismic velocity observations with physical and chemical properties of mantle rocks, resulting in large uncertainties that obscure firm conclusions. An additional uncertainty arises because there is currently no primary scale for accurately measuring pressure at high temperatures. In this study mineral sound velocities and densities will be measured in the diamond anvil cell at simultaneous high pressures and high temperatures to at least 50 GPa and 1300K. This will be possible by a pioneering combination of Brillouin scattering spectroscopy, to measure sound velocities, and single crystal X-ray diffraction determinations of density. By making both types of measurements on the same sample while it is maintained at a constant pressure and temperature, the pressure can be independently measured. These absolute pressure determinations will be used to derive a new universal pressure scale for use at high temperatures. Sound velocities of the major mantle minerals will be determined at high temperatures and absolute pressures thereby drastically decreasing the uncertainties in velocity calculations for rock assemblages at deep mantle conditions. The resulting data will be employed to finally interpret a host of seismic observations made at both global and local scales.

SummaryThis project aims at revolutionizing the way the emission of mineral dust from natural soils is treated in numerical models of the Earth system. Dust significantly affects weather and climate through its influences on radiation, cloud microphysics, atmospheric chemistry and the carbon cycle via the fertilization of ecosystems. To date, quantitative estimates of dust emission and deposition are highly uncertain. This is largely due to the strongly nonlinear dependence of emissions on peak winds, which are often underestimated in models and analysis data. The core objective of this project is therefore to explore ways of better representing crucial meteorological processes such as daytime downward mixing of momentum from nocturnal low-level jets, convective cold pools and small-scale dust devils and plumes in models. To achieve this, we shall undertake (A) a detailed analysis of observations including station data, measurements from recent field campaigns, analysis data and novel satellite products, (B) a comprehensive comparison between output from a wide range of global and regional dust models, and (C) extensive sensitivity studies with regional and large-eddy simulation models in realistic and idealized set-ups to explore effects of resolution and model physics. In contrast to previous studies, all evaluations will be made on a process level concentrating on specific meteorological phenomena. Main deliverables are guidelines for optimal model configurations and novel parameterizations that link gridscale quantities with probabilities of winds exceeding a given threshold within the gridbox. The results will substantially advance our quantitative understanding of the global dust cycle and reduce uncertainties in predicting climate, weather and impacts on human health.

This project aims at revolutionizing the way the emission of mineral dust from natural soils is treated in numerical models of the Earth system. Dust significantly affects weather and climate through its influences on radiation, cloud microphysics, atmospheric chemistry and the carbon cycle via the fertilization of ecosystems. To date, quantitative estimates of dust emission and deposition are highly uncertain. This is largely due to the strongly nonlinear dependence of emissions on peak winds, which are often underestimated in models and analysis data. The core objective of this project is therefore to explore ways of better representing crucial meteorological processes such as daytime downward mixing of momentum from nocturnal low-level jets, convective cold pools and small-scale dust devils and plumes in models. To achieve this, we shall undertake (A) a detailed analysis of observations including station data, measurements from recent field campaigns, analysis data and novel satellite products, (B) a comprehensive comparison between output from a wide range of global and regional dust models, and (C) extensive sensitivity studies with regional and large-eddy simulation models in realistic and idealized set-ups to explore effects of resolution and model physics. In contrast to previous studies, all evaluations will be made on a process level concentrating on specific meteorological phenomena. Main deliverables are guidelines for optimal model configurations and novel parameterizations that link gridscale quantities with probabilities of winds exceeding a given threshold within the gridbox. The results will substantially advance our quantitative understanding of the global dust cycle and reduce uncertainties in predicting climate, weather and impacts on human health.

SummaryThis project aims to directly constrain the melting history and composition of the mantle of the Earth
for the first 750 Ma of its history. So far, our limited knowledge hinges on isolated detrital zircons from
Archean crustal rocks. They indicate crustal extraction as early as 4.4 Ga with peaks at 4.0 and 4.3 Ga but
reveal conflicting models for the composition of the Hadean mantle. Both the timing and extent of these
early crust formation events and the composition of the Hadean mantle have crucial implications for our
understanding of the Early Earth’s chemical evolution and dynamics as well as crustal growth and thermal
cooling models. Sulfides (BMS) and platinum group minerals (PGM) may hold the key to these fundamental
issues, as they are robust time capsules able to preserve the melting record of their mantle source over
several billion years.
I propose to perform state-of-the-art in-situ Pt-Re-Os isotopic measurements on an extensive
collection of micrometric BMS and PGM from Archean cratonic peridotites and chromite deposits, and
paleoplacers in Archean sedimentary basins. For the first time, < 20 μm minerals will be investigated for Pt-
Re-Os. The challenging but high-resolution micro-drilling technique will be developed for in-situ sampling
of the PGM and BMS with subsequent high-precision 187Os-186Os isotopic measurements by NTIMS. This
highly innovative project will be the first to constrain Hadean Earth history from the perspective of the
Earth’s mantle. By opening a new window towards high-precision geochemical exploration for micrometric
minerals, this project will have long-term implications for the understanding of the micro to nano-scale
heterogeneity of isotopic signatures in the Earth’s mantle and in extra-terrestrial materials.

This project aims to directly constrain the melting history and composition of the mantle of the Earth
for the first 750 Ma of its history. So far, our limited knowledge hinges on isolated detrital zircons from
Archean crustal rocks. They indicate crustal extraction as early as 4.4 Ga with peaks at 4.0 and 4.3 Ga but
reveal conflicting models for the composition of the Hadean mantle. Both the timing and extent of these
early crust formation events and the composition of the Hadean mantle have crucial implications for our
understanding of the Early Earth’s chemical evolution and dynamics as well as crustal growth and thermal
cooling models. Sulfides (BMS) and platinum group minerals (PGM) may hold the key to these fundamental
issues, as they are robust time capsules able to preserve the melting record of their mantle source over
several billion years.
I propose to perform state-of-the-art in-situ Pt-Re-Os isotopic measurements on an extensive
collection of micrometric BMS and PGM from Archean cratonic peridotites and chromite deposits, and
paleoplacers in Archean sedimentary basins. For the first time, < 20 μm minerals will be investigated for Pt-
Re-Os. The challenging but high-resolution micro-drilling technique will be developed for in-situ sampling
of the PGM and BMS with subsequent high-precision 187Os-186Os isotopic measurements by NTIMS. This
highly innovative project will be the first to constrain Hadean Earth history from the perspective of the
Earth’s mantle. By opening a new window towards high-precision geochemical exploration for micrometric
minerals, this project will have long-term implications for the understanding of the micro to nano-scale
heterogeneity of isotopic signatures in the Earth’s mantle and in extra-terrestrial materials.